The present invention relates to a magnetic head circuit, a magnetic disk unit having a read/write integrated circuit for driving a magnetic head, and a magnetic disk control method.
Examples of known magnetic head driving circuits are disclosed in K. B. Klassen, "MAGNETIC RECORDING CHANNEL FRONT-ENDS", IEEE TRANSACTIONS ON MAGNETICS, Vol. 27, No. 6, November 1991, pp. 4503-4508; U.S. Pat. No. 4,706,138, U.S. Pat. No. 4,786,993, U.S. Pat. No. 4,743,861, and U.S. Pat. No. 4,914,398; and JP-A-62-273609, JP-A-60-201505 and JP-A-63-257903. Examples of known magnetic-head-abnormality detection circuits are described in JP-A-60-136910, JP-A-61-178779, JP-A-61-170909, and JP-A-Hei-3-104006. An example of known reading circuits is given in JP-A-61-42706.
Higher memory capacity, higher data transfer rate, smaller size and higher reliability in magnetic disk units have increasingly been demanded. For meeting such demands, the inventors of the present application have again examined and investigated the so-called read/write integrated circuit for driving a magnetic head. As a result of the reexamination, the inventors have found various requirements for higher speed write system circuits to attain a higher data transfer rate, for higher speed read system circuits for larger memory capacity, for protection of elements from the higher voltage required for meeting higher speed requirements, and also for detecting an abnormality in the magnetic head with high accuracy, which requirements must be satisfied.